Expected Velocities

What are the usual velocities of blood found in the human vascular system?

Normal human peak systolic blood flow velocities vary with age, cardiac output, and anatomic site. At the aortic valve, peak velocities of up to 500 cm/sec may be possible. The ascending aorta has the highest average peak velocities of the major vessels; typical values are 150-175 cm/sec. Flow in the distal aorta and iliac vessels slows to the 100-150 range, whereas peak velocities in the proximal carotid, brachial, and superficial femoral arteries are about 80-110 cm/sec. Intracranially, peak velocities of the middle and anterior cerebral arteries are approximately 40-70 cm/sec, whereas those in the vertebral-basilar system are only 30-50 cm/sec. Venous velocities are generally less than 20 cm/sec. Conversely, in certain pathological conditions such as arteriovenous fistulas, velocities up to 400 cm/sec may be recorded.

*High-grade ICA stenoses may have peak velocities of 300 cm/sec and jets from aortic stenoses as high as 500 cm/sec